An organic electroluminescence element is a thin-type complete solid element utilizing electroluminescence produced by an organic material (hereafter, the term “electroluminescence” is also simply called as “EL”) and enabling to emit light at a voltage of approximately a few to a few tens volts. It has many excellent features of high luminance, high emission efficiency, thin-type, and lightweight. Therefore, particularly in recent years, an organic EL element using a resin substrate provided with a thin and lightweight gas barrier layer attracts attention as a surface-emitting body used for a backlight in various displays, a display panel of sign or emergency light, or an illuminating light source.
However, with respect to this organic EL element using a resin substrate, it is required a gas barrier property of extremely high level almost as high as a glass substrate. In particular, it is demanded an organic EL element which can prevent generation of dark spots even keeping for a long term under the condition of high temperature and high humidity such as 85° C. and 85% RH.
In addition, with respect to a bottom-emission type organic EL element, it is required to take out light emitted in the electric field light emitting layer uniformly and efficiently.
As a resin substrate for a flexible organic EL element, for example, a gas barrier substrate utilizing a polysilazane reforming layer is disclosed (for example, refer to Patent document 1: Japanese patent application publication (JP-A) No. 2014-109001).
However, the flexible organic EL element disclosed in the aforesaid Patent document 1 has not achieved the level of preventing generation of dark spots after keeping for a long term under the condition of high temperature and high humidity such as 85° C. and 85% RH. Further, there is a problem of deterioration of emission efficiency and emission uniformity of the organic EL element due to a reflection phenomenon of light at an interface between a polysilazane reforming layer and an electrode.